\documentclass[a4paper]{jreport} \usepackage{titlesec} \usepackage{picture} \usepackage[usenames]{color} %\usepackage[usenames,divpsnames]{xcolor} % colors \definecolor{teal}{RGB}{0,128,128} \definecolor{powderblue}{RGB}{176,224,230} \definecolor{darkslateblue}{RGB}{72,61,139} \definecolor{darkslategray}{RGB}{47,79,79} \definecolor{lightcyan}{RGB}{224,255,255} % chapter \titleformat{\chapter}[bloc